The present invention relates generally to magnetic resonance imaging (MRI), and more particularly to an MR imaging system and a method to reconstruct an MR image using both a partial, or fractional, k.sub.x data acquisition and a partial, or fractional k.sub.y data acquisition to reduce total acquisition scan time.
In MR imaging, to date, the scan time can be reduced by using a partial k.sub.x data set, also known as a partial echo, or a partial k.sub.y data set, also known as a partial NEX (number of excitations in ky), but not both. By acquiring a fractional echo, the echo times in MR imaging are reduced by shifting the echo formation to a time earlier in the readout window. The missing data can be reconstructed by either zero-filling along the k.sub.x direction prior to Fourier transformation, or by using a homodyne or partial k-space reconstruction technique. Under both reconstruction techniques, at least 50% of the data must be acquired. Similarly, obtaining a fractional NEX reduces the total acquisition time by acquiring either slightly more than half of the views of a full NEX to approximately three-quarters of the views of a full NEX. As in fractional echo, the missing data is either zero-filled or estimated with a homodyne or partial k-space reconstruction technique. Current methods do not allow the reconstruction of both a partial echo and a partial NEX data acquisition in the same MR image.
Therefore, it would be desirable to have a system and method capable of combining both a partial echo and a partial NEX to reduce both acquisition times and echo times in MR imaging without significant blurring effects in the resulting image.